Part 3 of our 3D Printer build.
- In this part of our printer assembly, we:
- Mounted the filament spool holders
- Installed the LCD panel and SD card reader
- Installed endstops
- Installed the bottom fan and power supply
- Installed the X, Y and Z axis motors
- Installed the filament extruders
- Installed the main control board
- Installed cabling for the motors and endstops
- Time for this step: 5 hours
- Total build time: 7 hours 50 minutes
This is the third stage of our 3D printer kit build. For the background to the project and details of the kit we are using, take a look at the introductory page here, or click here to see all our posts about this project.
First we assembled the filament spool mounts. These need to run as freely and smoothly as possible so the distance between the two bearings has to be measured precisely.
Once set at the correct distance apart the bearings nestle smoothly into the spool body.
The completed spool holder mounted onto the printer.
The next step was to install the LCD panel and SD card reader. This allows the printer to be operated independently of a computer.
The LCD panel mounted on the front panel of the printer. We left off the encoder knob which will eventually be attached to the board for now (it fits onto the silver shaft visible in the top left of the previous picture) as it could easily be damaged during the remaining stages of assembly.
Routing the ribbon cable for the LCD panel below the bottom of the printer.
In the next step, we installed the X, Y and Z axis endstops. These are simple optoelectronic devices that allow the printer to detect the limit of motion in a particular axis by sensing when an infra-red beam is interrupted.
Mounting the endstop boards onto the side of the printer.
We next installed a fan into the bottom panel, which will help to cool the electronics which sit below the base of the printer.
In this picture you can see the three stepper motors which will move the print head in the X and Y axis, and the build platform in the Z axis.
Installing the motors involves placing a pulley onto the motor shaft and setting it the correct distance along the shaft, then tightening it in position with a small set screw. The set screw threads are easily stripped, so we used Loctite medium strength threadlocker compound (Loctite 243) to help hold them in place without using excess force to tighten them.
Fitting the mounts onto the motor.
The Z axis motor in place. This motor has no pulley as it will drive a threaded rod via means of a coupler to be added later.
One of the X and Y axis motors mounted next to its endstop. The motors are only loosely mounted for now as they will be precisely positioned at a later stage.
The X and Y axis motors in place. You can see the X, Y and Z axis endstops in position.
Once the motors were mounted, we moved on to assembling the filament extruders. The extruder consists of a stepper motor which turns a grooved pulley, and a spring loaded lever which presses a bearing against the pulley. The filament is drawn up by the pulley and into the tube fitting on top, where it goes into a PTFE tube and up to the print head.
The picture below shows the parts which make up the extruder. As with the X and Y axis motors, the pulley is held onto the motor shaft by a very small set screw and threadlocker compound should be used to avoid over-tightening it.
Mounting the spring loaded lever which presses a bearing against the pulley (visible in the centre). The lever can be pressed down to release the tension to load and unload filament.
We now moved on to mounting the main control board for the printer. The first step is to install driver boards for each of the stepper motors. Each one of the modules below drives one motor and slots into a socket on the main board. When we researched this kit beforehand, there were some users reporting that the driver chips can get very hot in use, so we purchased separately some small SMD heatsinks and attached them to each driver chip using thermal tape.
The first driver module mounted into the main board (top left).
Installing the main control board on to the underside of the bottom panel and wiring in a cable which will connect to the power supply.
Connecting the reset switch and the ribbon cable from the LCD panel.
Once the main control board is in place, the wiring harnesses for the various motors and endstops and for the print head can be connected. Each wire is labelled at both ends to make it easier to work out what goes where. It doesn’t make it any easier to manage this spaghetti of cables though – thankfully plenty of small cable ties are provided with the kit to help get everything under control, but you’ll need to supply the patience!
The main control board connections completed and tidied up – the mess of cables above will be routed into the printer and connected to the various motors in the next step.
That’s all for this part – in the next instalment we will be mounting the power supply and then really getting into the guts of the printer as we assemble and mount the print head.
Keep an eye on the 3D Printing section for all the posts about our build, post questions in the comments or tweet us at @dannynic or @sarah_nic.
